1. Field of the Invention
The present invention relates to a grinding method of and a grinding machine for grinding a workpiece with a rotatable grinding wheel wherein coolant is reliably supplied to a grinding point by cutting off air layer flowing on a circumferential surface of the grinding wheel.
2. Description of the Related Art
It is typically known for a grinding machine to grind a workpiece by a grinding wheel rotated at high speed. FIG. 1 shows a method of supplying a high pressure of coolant, in which a nozzle 60 supplies highly pressurized coolant at high speed to a grinding point grinding the workpiece by the grinding wheel G in order to cut off air layer flowing on a circumferential surface of the grinding wheel G. FIG. 2 shows a method of supplying a coolant perpendicularly, in which a supply port of a coolant nozzle 61 is faced to an circumferential surface of a grinding wheel G to supply coolant perpendicularly thereto. And also, it is typically known for an ecology grinding to supply atomized lubrication oil, which is mixed lubrication oil with compressed air supplied from an air source, from a nozzle to a grinding point and to supply a small amount of coolant to a workpiece for cooling the workpiece.
The high pressure supplying method of coolant or the perpendicular method of coolant of the typically known grinding machine can not reliably and efficiently cut off said air layer flowing on the circumferential surface of the grinding wheel. And also, in the high pressure supplying method of coolant or the perpendicular method of coolant of the typically known grinding machine, since coolant is compulsorily supplied to reach the circumferential surface against air layer flowing on the circumferential surface, it therefore needs inevitably high pressure and large volume of coolant. Where the high pressure or the large volume coolant is used, it needs not only a huge cost maintaining clean in coolant but also make an environmental problem in a waste process of the large volume of coolant. And also, in the ecology grinding of the typically known grinding machine, stream of supplied coolant is week because of the small amount of coolant so that it is difficult for supplying coolant reliably with a disturbance by air layer flowing on the circumferential surface of the grinding wheel.
The applicant filed the patent application to cut off air layer flowing on a circumferential surface of a grinding wheel at an upper stream position of a rotational direction of the grinding wheel from a grinding point. In a grinding machine grinding a workpiece by the grinding wheel rotated at high speed of this application, air jet is blown transversally from one side to the other side of the grinding wheel along the circumferential surface at the upper stream position of the rotational direction of the grinding wheel from the grinding point in order to cut off said air layer flowing on the circumferential surface of the grinding wheel reliably to supply coolant to the grinding point. When said air jet is blown transversally along the circumferential surface from said one side to the other side of the grinding wheel, coolant flown with said air jet on the circumferential surface of the grinding wheel from the grinding point is blown by said air jet so that mist of coolant is scattered to atmosphere around over the grinding machine to cause a bad environment in a factory.